Oil burner



W. O. BEHRENS UIL BURNERv June 4, 194C.

Filed July ll, 1936 Zzdezzfor /L/Zz'a/zz 0. Be/areas y; ya@

v Patented `lune 4, 1940 UNITED STATES PATENT OFFICE OIL BURNER WilliamO. Behrens, Harvey, Ill.

Application July 11, 1936, Serial No. 90,232

6 Claims;

The present invention relates to improvements in oil burners.

' air is supplied byl forced draft, and more speciiically in whichprimary air is supplied by a high pressure fan, and in which a lowpressure fan supplies secondary air and also the air for the highpressure fan.

A further object is to providetwo fans discharging in series andparallel, and driven jointly.

'from a common source, the first fan having a' relatively large capacityand a low pressure output, and the second fan having a relatively smallcapacity and high pressure output.

Other objects of the invention are to provideI a novel oil burner whichis eiiicient in operation,v

which effects a thorough mixing of air and fuel, and in which the lowpressure air is controlled with the fuel supply, so that the fire isnever lazy and smoky and the eiiiciency does not vary with the draft.

Further objects and advantages will become apparent as thedescription/proceeds.

In the accompanying drawing, Figure 1 is a longitudinal sectional viewof an oil burner embodying the'features of my invention.

Figs. 2 and 3 are transverse sectional views taken respectively alonglines 2-2 and 3,-3v

stream of air and finely atomized fuel oil into a furnace. In thepresent instance, a fragment of the furnace is illustrated, the furnacehaving air fan or blower 2l.

a refractory wall 4 formed with a burner opening 5. A burner front plateB is secured against the exterior of the wall 4, and has an opening I inregistration with the opening 5.

vThe burner has a low pressure air nozzle 8 extending into the opening5. Preferably, the

lnozzle 8 is in the shape of a Venturi tube. The

peripheral wall of the opening 5 is shaped to conform to the nozzle 8.An outer peripheral flange 9 on the inlet end of the nozzle 8 issecurely bolted to the plate 6.

The nozzle 8 opens from a housing Ill enclos- 4ing a low pressure airfan or blower II, and having a cover I2. 'Ihe housing is suitablysupported, with thel coverv I2 in position against the flange 9. Thecover I2 is formed with a flange I3 tapered internally to provide acontinu ation of the nozzle 8, and the portion thereof circumscribedbythe flange I3 constitutes a radially disposed plate member IIIterminating in a concentric inner ring I5. A rotary damper or shuttermember I6 is disposed against the member y I `4, and is adjustable bymeans of a rod II pivotally connected to one side, as illustrated inFig. 2,

and extending out of the housing I0. Themembers I4 and I6 haveperipheral spaced openings I4a and Ilia movable into various degrees ofregistration to regulate the amount of air discharging through thenozzle 8.'

Extending coaxially through the nozzle 8 is a high pressure air nozzleI8. This nozzle is tapered so that the intervening annular air spacebetween the nozzles is of gradually increasing flow area. The nozzle I 8is mounted on the end of a' tube I9 which extends through and issupported in the ring I5, and which constitutes the axial outlet of ahousing 20 enclosing a high pressure The tube I9 also supports thedamper member I6.

The blower 2| may be of any suitable form, and in the present instancehas an axial inlet taking low pressure air through an axial opening 22in the housing 29 from the housing I0, and has a peripheral discharge. Acircular balile or guide plate 23 is mounted substantially in the centerI of the housing 20, and serves to direct air from the peripheryinwardly to the tube I9.` Likewise, the low pressure blower II.,although smaller in diameter than the blower 2|, has an axial inlet anda. peripheral discharge into the housing I Il. A baffle or guide plate24 is disposed between the blowers II and 2l to direct air from thehousing I0 to the inlet opening 22 of the housing 20.

Secured to and closing one side of the housing IIJ is a cylindricalhousing 25 having a plurality of air inlets 25, 21 and 28 opening fromthe atmosphere. The inner end wall of the housing 25 is formed with anaxial outlet opening 29 which communicates with the housing I0, and

which is in direct registration and closely interfitting relation withthe inlet of the blower I I.

The two blowers I I and 2l are mounted ooaxially on a common drive shaftB which is journalled in spaced bearings 3i and 32 in opposed walls of agear chamber 33 Within the housing 25. The outer end of the shaft 38 isalso supported in a sleeve 3G on a valve body 35 mounted on the outerend of the housing 25. able means may be provided for driving the shaft30, and in the present instance this means comprises an electric motor36 having a casing 3l built into the outer end of the housing 25 betweenthe gear chamber 33 and the valve body 35.

Mounted for rotation Coaxially Within the high pressure air nozzle I8and coacting therewith to define a tapered annular air passage is asubstantially cylindrical atomizing cup 38 which is fixed on the innerend of the shaft 3U, and the interior of which is flared toward and openat the outer end. Extending longitudinally through the shaft 30, whichis hollow for this purpose, is an elongated fuel supply tube 39. Anozzle 40 is mounted on the outlet end of the tube 39 within theatomizer cup 38. The other end of the tube 39 is fixed in the valve body35, and in communication with a passage @I 'adapted to be connected by athrottle valve I2 to a tube i3 leading from a pump (not shown). The pumphas a drive shaft 44 which extends transversely of the shaft 30 into thegear chamber 33 for a drive connection with the motor 36. In the presentinstance, the shafts are connected by a worm l5 and worm wheel 45, andthe latter dips into a lubricant in the bottom of the chamber 33. Theair shutter I6 and the fuel valve L32 are interconnected for jointoperation from a single actuator 32a which may be operated manually. Tothis end, the rod ll is pivotally connected to one arm of a bellcranklever 41 pivoted on the housing i0. 'I'he other arm of the lever 41 isconnected by a rod I8 to a crank arm 159 on the plug of the valve 42. Aturnbuckle 50 is interposed in the rod i8 and affords means foradjusting the ratio of low pressure air to fuel. To insure an intimatefuel mixture and ne atomization of the fuel, two sets of peripherallyspaced helical vanes 5I and 52 are disposed respectively in the annularlow pressure and high pressure air discharge passages. These sets ofvanes are oppositely inclined and rigid respectively with the nozzles 8and i8. Nozzles with vanes of different inclination may be substituteddepending on the nature of the flame desired. Thus, the flame may belong and narrow or short and wide. The vanes are so orientated that,assuming the cup 38 as rotating clockwise, the high pressure primary airis discharged counterclockwise, and the low pressure secondary air isdischarged clockwise.

The oil burner with the speciiic features of the nozzle structure hereindisclosed, but indef pendent of the air and fuel regulating means and ofdetails of the air supply means, is claimed in my copending applicationSerial No. 150,279, filed June 25, 1937.

In operation, air enters the housing 25 through the openings 26, 2I and28, cools the motor 36, and passes to the blower I I. It is dischargedinto the housing IU, and passes from there in part to the nozzle 8 andin part to the blower 2l. The

Any suitair from the blower 2l passes to the nozzle I8. Fuel is suppliedthrough the valve '32 and the tube 39 to the nozzle dll from which it isdischarged into the revolving atomizing cup 33. The fuel and air areintimately mixed. When the flame is turned down, the shutter I3 isadjusted to reduce the volume of low pressure secondary air, but thefull supply of primary air is maintained. As a result, the flame isnever lazy or smoky, and a high efficiency is always maintained.

I claim as my invention:

1. In an oil burner, in combination, a secondary air nozzle, asecondary` air housing in cornmunication with said nozzle, a primary airnozzle coaxially associated with said secondary air nozzle, a highpressure low capacity blower in said housing for discharging air to saidprimary air nozzle and having an inlet open to the interior of saidhousing, a fuel nozzle extending into said primary air nozzle, a lowpressure high capacity blower mounted in and discharging air to saidhousing and having an atmospheric air inlet, said rst mentioned blowerhaving relatively long and narrow blades,- with a relatively largeexternal circle of revolution and said second mentioned blower havingrelatively short and broad blades with a relatively small externalcircle of revolution, and a drive shaft for said blowers extendingaxially of said nozzles.

2. An oil burner comprising, in combination, associated primary andsecondary air nozzles, a fuel nozzle associated with said primary airnozzle, a high pressure blower for supplying air to said primary airnozzle, a low pressure blower for supplying air to said high pressureblower and to said secondary air nozzle, means for supplying fuel tosaid fuel nozzle, means for regulating the fuel supply, means forregulating the supply of secondary air from said low pressure blower tosaid secondary air nozzle, and manually operable means interconnectingthe fuel supply regulating means and the secondary air supply regulatingmeans for joint operation, whereby an increase in the fuel supplied willbe accompanied by a corresponding' increase in the supply of secondaryair.

3. In an oil burner, in combination, an external secondary air housinghaving an atmospheric air inlet in one side and an aligned secondary airoutlet in the other side, a secondary air nozzle connected to saidhousing and communicating with said outlet, an internal air housingrigidly mounted within said external housing and in spaced relationthereto and having an air inlet in one side opening from said externalhousing and an aligned primary air outlet in the other side, a primaryair nozzle mounted in said eX- ternal housing and communicating withsaid primary air outlet and extending in concentrically spaced relationthrough said secondary nozzle, a ldrive shaft extending coaxiallythrough said housings, a rotary propeller having a closed end disk fixedon said shaft in axially spaced relation to said internal housing andhaving a plurality of short wide vanes with a relatively small externalcircle of revolution in annularly spaced relation on the side of saiddisk remote from said internal housing, the inner ends of said vanesextending partially across said firstr mentioned inlet, air from theperiphery of said propeller being directed by said external housingabout said internal housing to said first mentioned outlet. means fordirecting air from the periphery of said propeller radially inwardly tosaid second mentioned inlet, a second propeller having a closed end diskfixed on said shaft within said internal housing and having a pluralityof annularly arranged narrow long vanes of a relatively large externalcircle of revolution on one side of said last mentioned disk, the innerends of said last mentioned vanes extending partially across said secondmentioned inlet, air from the periphery of said second mentionedpropeller being directed by said internal housing radially inwardly tosaid second mentioned outlet, means for supplying fuel oil axiallythrough said shaft and including a fuel nozzle for discharging fuelthroughsaid `primary air nozzle, and means for rotating said shaft.

'4. An oil burner comprising, in combination, primary and secondary airnozzles, a fuel nozzle extending into said primary air nozzle, means forsupplying high pressure air to said primary nozzle and low pressure airto said secondary air nozzle, means for supplying fuel oil to said fuel'nozzle, means for regulating the fuel supply, means for regulating thevolume of air supplied to said secndary air nozzle, and meansinterconnecting said last two 'mentioned means for joint synchronousoperation, whereby an increase in the fuel supplied will be accompaniedby a proportional increase in the supply of secondary air. y

5. An oil burner comprising, in combination, primary'and secondary airnozzles, a fuel nozzle extending into said primary air nozzle, means forsupplying high pressure air to said primary air nozzle and low pressureair to said secondary air nozzle, means for supplying fuel oil to saidfuel nozzle, means forregulating the fuel supply, means for regulatingthe volume of secondary air, and means interconnecting said last twomentioned means for joint synchronous operation, whereby an increase inthe fuel supplied will be accompanied by a proportional increase in thesupply of secondary air.

6. An oil burner comprising, in combination, primary and secondary airnozzles concentrically mounted to discharge coaxially into a furnace, afuel nozzle extending into said primary air nozzle, means including aquantity regulating means for supplying fuel oil to said fuelnozzle, ahigh pressure blower for supplying air to said primary nozzle, a lowpressure blower for supplying air to said secondary air nozzle, a damperinterposed between said low pressure blower and said secondary air`nozzle for controlling the supply of air to said secondary air nozzle,and means interconnecting said regulating means and said damper, saidlast mentioned means being manipulable for joint operation of saidregulating means and said damper and being adjustable as lto its lengthto vary the ratio of secondary air t vfuel oil.

WILLIAM O. BEHRENS.

